Jack Kenny, Editor10.21.09
At the Massachusetts Institute of Technology (MIT), viruses are making batteries. This seemingly farfetched practice is the work of a team of scientists who have genetically engineered viruses to produce the components of a microscopic battery, which then can be printed onto a substrate.
Led by Angela M. Belcher, professor of biological engineering and materials science and engineering, the team says that the batteries can be transferred to a number of different types of surfaces. They measure about five microns in width, and conceivably could be used in the medical industry to provide power sources for implants and other devices, as well as in other industries.
Belcher, who was named 2006 Research Leader of the Year by Scientific American magazine, says that interest in the process from outside the academic environment has been strong, but notes that the MIT group has yet to publish a final report of its next generation research, and so discussion of commercialization of the process is premature.
The viruses, says Belcher, are bacteriophages, which are common in our surroundings. They are not harmful to humans, but instead infect bacteria. The viruses are not capable of reproducing on their own, but must use the bacterial host for that purpose.
“The point for us is not that it’s a virus, but rather a biological material that has a really nice structure and a nice aspect ratio – it’s shaped like a wire. We made small changes in its DNA sequence so that it could build crystals. The process involved easy molecular biology to make those changes.” The changes resulted in a host-virus interaction that produced the materials necessary for the anode, cathode and electrolyte of the battery.
“The same way that an abalone grows a shell, by grabbing calcium out of its environment, the viruses produce the battery components,” she adds. Early in her career Belcher studied abalone and the process it employs to create its shell, which is 3,000 times stronger than chalk.
Cobalt oxide was the material used for the anode, Belcher says, because it has a high specific capacity, a high energy density. “But it’s not the ideal material for this kind of system. You have to match the properties of your anode and cathode to give you the best possible cell, and there are lots of other materials besides cobalt. We have been working on other kinds of metals and metal oxides. More important, on the other half of the battery, you have to consider what makes the best batteries that give the best performance, and are amenable to these kinds of processing conditions. In the last couple of months we have been pretty excited by materials we’ve been using.”
As for production of the battery materials, the process of nucleation takes hours, she says. The MIT team has been working on a scale of milligrams of material for its research, but Belcher expects that production can be accomplished on a large scale. One of the goals of the team is to scale up its battery component size to grams and beyond.
In the early stages of the research the team was able to create the material for the anode but not the cathode. Success in viral production of the cathode came early this year, and work on the final aspects of the project is under way today.
The actual printing process – the transfer of the virally created material to a substrate – is in the form of stamping. This aspect of the research was overseen by MIT Professor Paula Hammond. “We use weak polymer electrolytes, and build them up layer by layer on a stamp,” says Belcher. “When that’s complete, we engineer the biological component to line up on the polymer through electrostatic interaction. The virus is sequenced to grow the battery electrode, and then it’s stamped down on one part of the battery. The other component is stamped on top of that.”
“We got a little hung up – not on ability to stamp these components, but on some of the materials themselves for the cathodes,” she observes. “Basically we didn’t have an ideal match between the materials used for anode and cathode. In the last couple of weeks we solved that problem in terms of better materials that are compatible. We’ve made good progress toward solving all of the issues, and now we hope to focus on making these stamped thin film batteries.”
The process of employing viruses to manufacture the battery components is quite green and does not involve processes that adversely affect the environment. That aspect will surely be considered by commercial companies that are interested in the MIT process.
The virally produced batteries have admirers in high places, it appears. In March, MIT president Susan Hockfield demonstrated the prototype battery to US President Barack Obama. At a White House briefing on green energy technologies, Hockfield said flexible battery films could be manufactured near room temperature using environmentally benign processes.
Led by Angela M. Belcher, professor of biological engineering and materials science and engineering, the team says that the batteries can be transferred to a number of different types of surfaces. They measure about five microns in width, and conceivably could be used in the medical industry to provide power sources for implants and other devices, as well as in other industries.
MIT Professor Angela Belcher
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The viruses, says Belcher, are bacteriophages, which are common in our surroundings. They are not harmful to humans, but instead infect bacteria. The viruses are not capable of reproducing on their own, but must use the bacterial host for that purpose.
“The point for us is not that it’s a virus, but rather a biological material that has a really nice structure and a nice aspect ratio – it’s shaped like a wire. We made small changes in its DNA sequence so that it could build crystals. The process involved easy molecular biology to make those changes.” The changes resulted in a host-virus interaction that produced the materials necessary for the anode, cathode and electrolyte of the battery.
“The same way that an abalone grows a shell, by grabbing calcium out of its environment, the viruses produce the battery components,” she adds. Early in her career Belcher studied abalone and the process it employs to create its shell, which is 3,000 times stronger than chalk.
Cobalt oxide was the material used for the anode, Belcher says, because it has a high specific capacity, a high energy density. “But it’s not the ideal material for this kind of system. You have to match the properties of your anode and cathode to give you the best possible cell, and there are lots of other materials besides cobalt. We have been working on other kinds of metals and metal oxides. More important, on the other half of the battery, you have to consider what makes the best batteries that give the best performance, and are amenable to these kinds of processing conditions. In the last couple of months we have been pretty excited by materials we’ve been using.”
As for production of the battery materials, the process of nucleation takes hours, she says. The MIT team has been working on a scale of milligrams of material for its research, but Belcher expects that production can be accomplished on a large scale. One of the goals of the team is to scale up its battery component size to grams and beyond.
In the early stages of the research the team was able to create the material for the anode but not the cathode. Success in viral production of the cathode came early this year, and work on the final aspects of the project is under way today.
The actual printing process – the transfer of the virally created material to a substrate – is in the form of stamping. This aspect of the research was overseen by MIT Professor Paula Hammond. “We use weak polymer electrolytes, and build them up layer by layer on a stamp,” says Belcher. “When that’s complete, we engineer the biological component to line up on the polymer through electrostatic interaction. The virus is sequenced to grow the battery electrode, and then it’s stamped down on one part of the battery. The other component is stamped on top of that.”
“We got a little hung up – not on ability to stamp these components, but on some of the materials themselves for the cathodes,” she observes. “Basically we didn’t have an ideal match between the materials used for anode and cathode. In the last couple of weeks we solved that problem in terms of better materials that are compatible. We’ve made good progress toward solving all of the issues, and now we hope to focus on making these stamped thin film batteries.”
The process of employing viruses to manufacture the battery components is quite green and does not involve processes that adversely affect the environment. That aspect will surely be considered by commercial companies that are interested in the MIT process.
The virally produced batteries have admirers in high places, it appears. In March, MIT president Susan Hockfield demonstrated the prototype battery to US President Barack Obama. At a White House briefing on green energy technologies, Hockfield said flexible battery films could be manufactured near room temperature using environmentally benign processes.